A fluid treatment device generally uses one or several fluid treatment mediums to treat various fluids, such as water and so on, and generally contains one or more fluid treatment units accommodating the fluid treatment mediums. When fluid passes through a fluid treatment medium, the impurities and pollutant contained therein are removed by physical-chemical reaction with the treatment mediums. A typical example of such fluid treatment device is a device for purifying and softening water. By this device, on one hand, chemical pollutants, such as chlorine, heavy metals and sulfides, particle pollutants and the like in water are removed; and on the other hand, the water is softened due to removing calcium and magnesium in water. Such water treatment device may provide purified water suitable for direct drinking and washing water for families. Currently, it has been an important appliance for family life, especially for Chinese families.
Such device is disclosed in the prior art. For instance, U.S. Pat. No. 5,415,770 discloses that a fine grinding copper-zinc alloy is used to remove chemical pollutant (e.g., chlorine) during the pretreatment of water before being subjected to a water-softening ion exchange medium, whereby a lifetime of the ion exchange medium is prolonged. Alternatively, the fine grinding copper-zinc alloy may also be used to perform a post treatment to the water.
Publication document No. CN1232790A of Chinese patent application for invention also discloses a tank treatment assembly used for treating water. In the tank treatment assembly as disclosed, the water flows through each treatment unit by gravity and pressure, the each treatment unit comprises a chamber for accommodating a fluid treatment medium. The chamber has a substantially annular section. The water to be treated enters into the annular chamber from the top of the chamber, and the water treated by the treatment medium is discharged out of the chamber from the bottom of the chamber. In this treatment unit, as the water substantially flows along a diagonal of the chamber, both the flow route and the dwell time in the chamber are increased, thereby improving the treatment efficacy.
As for such treatment unit and a treatment device employing the same, it is necessary to perform a backwash washing frequently. This is because that dirt in the water will be deposited and adhered to the surface of the treatment medium. When the dirt excessively accumulates on the surface of the treatment medium, on the one hand, the treatment medium will lose efficacy, and on the other hand, the fluid will be “clogged” due to the pressure drop of the fluid flowing through the treatment unit being too large. Besides, when a water flow flows through the treatment medium from top to bottom, if the treatment medium has an uneven thickness in the treatment unit, then most of the water flow is prone to pass through a region where the treatment medium has a smaller thickness. That is to say, the treatment medium merely can partially exert its treatment efficacy.